Paediatric Tutorial for the Final FRCA
Some topics for short questions and vivas: this is not comprehensive!
Case scenarios:
Infant with Pyloric stenosis
Manipulation of closed fracture in 6 year old
Exprem infant for hernia repair
2 years old for tonsillectomy for obstructive sleep apnoea
An 11/2 old for a day case orchidopexy
A 3 year old with a peanut in the bronchus
A 2-week-old child for A VP shunt
A child with a cold
A child with a murmur
A child with asthma
A child with latex allergy
A child with sickle cell disease
Other topics:
Neonates:
Differences in anatomy and physiology b/n neonates and children and adults
Differences in pharmacology b/n neonates, children and adults
Paediatric anaesthetic equipment
Children:
Pain relief in children.
Caudal anaesthesia
Preoperative anxiolysis and premedication
Upper airway emergencies
Respiratory emergencies
Resuscitation
Scenarios:
How would you anaesthetise a four week old term infant with pyloric
stenosis?
What are the metabolic disturbances?
Dehydration, alkalosis, hyponatraemia, hypochloraemia
Renal response: excretion of alkaline urine then renal response to dehydration is to
retain sodium chloride and secrete hydrogen ions thus producing acid urine. Positive
feedback cycle leading to shock and prerenal failure.
How would you resuscitate this infant?
Depends on degree of insult. Colloid/isotonic saline to perfuse child. End points
urine output, cap refill. Dex 5%/0.45% saline+K 150ml/kg/24 hr. Monitor. End
points: PH normal, HCO3 <28, normal Na, K Cl> 100
How would you anaesthetise this infant?
Where? DGH or transfer?
Monitoring? Warming? Intraop fluids? Preinduction precautions?
Induction. RSI or Gas?. Pros and cons of each
Analgesia? Paracetamol (How much?) LA (how much?) , Codeine?
Postop complications?
When resume feeding?
Refs: “ Pyloric stenosis in Full term babies- a postal survey of management by paediatric anaesthetists” Peutrall et
al Paediatric Anaesthesia 1994; 4, 93-97
How would you anaesthetise a six year old with a forearm fracture for a
closed reduction. The child has no nerve or vascular injury. He has eaten two
hours before the trauma and it is now 12 hours since the trauma.
Points of discussion

Sedation in A/E or full theatre GA case?
o Logistic advantages of sedation by non anaesthesiogists
o “Efficacy and safety of Iv midazolam and ketamine as sedation for therapeutic and diagnostic
procedures in children” Parker et al Paediatrics 99, 3 1997

350 procedures (LPs , bone marrow aspirations)

non anaesthesiogists

4 hour starvation

Few complications

Regional or GA? Which regional technique?
o Biers block in kids?

“Outpatient treatment of upper extremity injuries in childhood using intravenous
regional anaesthesia” Olney et al J paedatr Orthop 8:576 1988

400 kids b/n 3-16.

Most good cooperation but needed preparation, premedication

Limb elevated for 30-60 s before tourniquet inflation to 200-250 mmHg

3mg/kg preservative free 0.5% lignocaine used

cuff inflated for 20 mins

good analgesia in 90%

in poor IVRA 84% still had surgery completed

15 patients plasma lignocaine levels measured 2/15 had lignocain in
circulation but below toxic range.

One complication: myoclonic muscle contractions
o Para scalene approach to the brachial plexus

“A new parascalene approach to the brachial plexus in children: comparison with
the supraclvicular approach”. Dalens et al Anesth Analg 66, 1264-71

RSI or LMA?
o “Anaesthesia for manipulation of forearm fractures in children: a survey of current practice”
Marcus et al Paediatric Anaesthesia, 10, 273-277(2000)

Aim : a survey of current practice, information obtained via a postal questionnaire

Questionnaire:

Results

fig 1;17% still do not perform RSI if eaten two hours before trauma and
given opioids

fig 2: paediatric anaesthetists the worst offenders
o why?

RSI no guarantee vs aspiration 10/19 cases of
aspiration in Warners survey from the Mayo
(Anaesthesiology 90, 1. jan 1999)

Sux has 1 in 5000 incidence of anaphylaxis

A closed claim analysis 47 for inadequate ventilation,
13 for oesophageal intubation and nine for difficult
ventilation. Only five for aspiration.
o But

AIMS study on critical incidents 60% of aspirations
could be avoided by RSI technique

Warner’s survey 10x risk of aspiration in emergency
surgery.

“ Gastric aspirates after trauma in children” Bricker
et al Anaesthesia 44 721-24 1989

volume and PH of gastric aspirates obtained
from 110 children (1-14) with limb or face
trauma. Injuries graded

RSI and stomach contents emptied via multiorifice NG tube.

Volume and PH noted

Correlated with time of last feed, time feed
to trauma and time from trauma to procedure








Median volumes both preanaesthetic fasting
and intake to trauma time important although
once PA time > 10 hours no difference
If food-trauma interval > 4 hours then no
patients were at risk of “dangerous”
aspiration. (>0.4 ml/kg and PH< 2.5)
Opioid administration no further bearing on
stomach emptying in trauma kids
Method probably underestimates stomach
contents
Volume and PH may not be all important as
solid material can cause morbidity
Vomiting common (21%) but no relationship
to stomach contents or fast times; mostly at
extubation
Severity of trauma an important determinant
of volume and PH but even trivial trauma
may have severe effects on.
All kids with trauma should have RSI

Is RSI effective?
o “Cricoid pressure in infants revisited” Anesthesiol 75, 3A 1991
What are the problems of anaesthetising children with colds?
Controversial area since some studies (1) suggest cough, laryngospasm and desaturation increases 2-7 x
and 11x if child intubated. Others (2) show no increase in risk for minor surgery but even this group report
increase risk in those with recent infection and intubated patients (3).
Pertinent factors in history: parental opinion (4), less than a year (1), fever and flu like features, productive cough
and LRTI. Delay for 4-6 wks (5)
Refs:
1. Cohen et al Should you cancel the operation if the child has an upper respiratory tract infection? Anaest
Analg 1991: 71: 282-8
2. Tait et al The effects of general anaesthesia on upper respiratory tract infections in children.
Anaesthesiology 1987; 67:930-50
3. Tait et al Intraoperative respiratory complications in patients with upper respiratory tract infections Can
J Anaest 1987; 34:300-3
4. Schreiner et al Do children who experience laryngospasm have an increased risk of upper respiratory
tract infection? Anesthesiology 1996; 85: 475-80
5. Empey et al Mechanisms of bronchial hyperactivity in normal subjects after upper respiratory tract
infections. AM Rev Resp Dis 1976 113:131
How would you manage a 1 yr old child who presents for an elective hernia
repair with a murmur?
How do you distinguish between an innocent and pathological murmur?
Asymptomatic, soft,early systolic, disappears on positioning, venous hum. Classic benign murmurs: left lower
parasternal honking and pulmonary flow murmur.
Asymtomatic murmurs: beware HOCM and critical aortic stenosis. So ECG mandatory to exclude LVH
(RV6+SV1>5 mm) . If ECG normal and other features of benign give antibiotics and refer for postop
investigation.
Ref:Mcewan et al Paediatric
Anaestesia 1995;5:151-6
How would you anaesthetise a 15mnth child for a day case orchidopexy?
Preoperative preparation.
Oral analgesics: Dosage of paracetamol. Rectal vs Oral. NSAI and the under 10kg, Asthma and NS
Psychological preparation: Age related, temprement, previous hospital experience. Interventions: Parental
presence? Preparation through play and information. Premedication.
Explanation of anaesthesia: Risks of GA, Caudal, Pain, PONV, mode of induction.
Anaesthesia
IV or gas? Gas Incremental or Full strength? Monitored before or after induction?
LM or tube?
Caudal:
Technique, easier in children<7 (Dalens et al noted failure of 1.5% vs 14.5% in the above 7s0
Doses:
Armitage 0.25% bupivicaine 0.5ml/kg Lumbosacral, 1 ml/kg thoracolumbar, 1.25 ml/kg midthoracic.
Wolf et al 0.125% =0.25% but less motor block .
Duration:
Increased with additives to bupivicaine. Epinephrine: 25% increase. Morphine (30-40ug/kg) Rd small risk
Mayhew et al 500 patients no significant RD. Clonidine and Ketamine. Caudal catheters.
Complications
Veycemans
etal
Broadman
Dalens and
Hasnaoui
Gunter
Giaufre et al
What are the causes of upper airway obstruction in children?
Notes :OSA: shorter and less common than centrral apnoeas but cause more hypoxaemia. PREM 68% OSA
OSA in older children due to T/A. Does polysomnography predict those with risk? What sort of monitoring
postop?
Rosen et al Paediatrics 1994; 93: 784: All children who had OSA diagnosed by PSG. Retrospective review.
37/324. 10/37 had POUAO after T/A surgery. The differences b/n those that had UAO and not were. Age ,2,
craniofacial abnormalities, F to T, Hypotonia, Morbid obesity. Previous airway trauma, Cor pulmonale.
Concomitant UPPP. Preoperative PSG RDI>40.
Children with mild OSA with no risk factors ICU may not be necessary. Helfaer et al looked at pre and postop
PSG in children with mild OSA. Improvement in PSG on first night.
Laryngomalacia: Commonest cause of stridor in neonates. Associated with subglottic stenosis. Developmental
delay. Self limiting. GA can cause further obstruction.
Postintubation stridor: Laryngospasm ,granuloma, membranes, webs and subglottic stenosis.
Koka: Risk of PIS :1-4yrs,traumatic intubation, tight fitting tube, moving when intubated, surgery>1 hour, surgery
on neck
Is the leak on the tube important? Khalil et al in 159 children: leak had no bearing on incidence of postoperative
croup. Only 50 without leak. Ops only 2 hours. No randomiisation
A comparison of tubes with cuffs and without again showed no differnce in incidence of croup. Both groups very
high incidence of PIS 2.4% vs 2.9% (Khine et al)
Problems with these studies: no standardisation on technique, length of intubation, leak size, defn of PIS.
Size of Cuffed tube? 3+age/4
Refs:
Khalil et al “Absence or presence of a leak around tracheal tube may not affect postoperative croup in
children. Paed Anaesth 1998; 8: 393-396
Khine et al “Comparison of cuffed and uncuffed endotracheal tubes in young children during general
anaesthesia” Anesthesiology 1997; 86: 627-631.
Epiglottitis:
Caused by H Influenza B. decreased incidence due to vaccine. Other pathogens implicated.
DD. Bacterial tracheitis gradual onset, barking cough and no dysphagia, dyspnea or sore throat.
Croup (see below)
Toxic appearance, anxious, sitting posn leaning forward neck extended.
Rx: No XR. Direct visual examination in theatre. Calm, upright, No a/way gags. IV? Monitors?
Gas induction. Agent? Preparation for Trache.
Intubation. Nasotracheal or leave orally?
Antibiotic. Third generation cephalosporin.
Hydration
Extubation in Theatre 24-48 hrs
Conservative watch and wait?
Croup
Viral (Parainfluenza). Subglottic oedema. Spasmodic croup and laryngotracheitis
Slow onset. Course 3-7ds.
DD. FB, E, subglottic tenosis, Lung disease, Angioneurotic oedema. Larynx masses.
Xray: useful 50% of time. Pencil sign.
Rx: Intubation rare 3%
Humidified air+oxygen:
Racemic epinephrine. Alpha effect causes mucosal vasoconstriction. One study showed no effect but others have
shown benefit: If use repeat every 1-2 hours. Beware rebound.
Steroids?
3yr old child who has a peanut in the bronchus.
Points of discussion:

Clinical features?
o “ Bronchoscopic removal of inhaled foreign bodies in children” Baraka BJA 1974, 46, 124

63 children b/n 1-3, mostly vegetables

Symptoms more severe with nuts: choking, cough, cyanosis, dyspnoea, stridor.

Delayed symptoms can be atelectasis, pneumonias, emphysema, lung abscess,
massive haemoptysis

Early presentation with nuts cf melon seeds

More widespread inhalation in nuts, fragmentation (can cause death during removal
when divided pieces occlude each main stem bronchus)

X-ray: 90% abnormal after 24 hours, hyper aeration of obstructed lung, atelectasis
and pneumonia less common (note get inspiratory and expiratory films)

Complications: cvs problems during brochoscopy-cardiac arrest (1), severe
subglottic oedema after operation (2), one went on to have tension pneumothorax.

An intermittent jet technique used for ventilating in this paper

Is this an emergency procedure?

Urgency depends on respiratory distress; more problems with proximal FB

If no RD then within 24 hours to minimise complications; do not give postural
drainage or physio

Should this be done in a non-specialist centre?

How do we anaesthetise this child
o Premed?
o Induction?

Iv or gas

Which agent?
o Paralyse or spontaneous breathing?
o Local anaesthetic spray?

How much
o Intubate before bronchoscopy or not?
o Type of bronchoscope?

Advantages of straight or tapered bronchoscopes
o Spontaneous breathing assisted or Jet (when?)

“ An evaluation of the jet injector technique for bronchoscopy in paediatric patients”
Miyasaka et al Canad. Aanaest Soc J 27 no 2 1980

two stage study evaluating the safety and efficacy with a lung model and a
small clinical trial
o Lung model: Saunders 19g adapter used with various
bronchoscopes

Fig 1:look at influence of bronchoscope shape; in
straight bronchoscopes inflation pressure rises sharply
with decrease in internal dia , not so with tapered

Fig 2: flow rate decreased with Int dia, small tapered
bronchoscopes have low flow

Fig 4: TV much less in a sick lung, varies with
inflation pressures but size of bronchoscope no
difference in sick lungs

Fig 5: in tapered bronchoscopes location of jet vital in
controlling maximal inflation pressures
o Clinical trial; 11 kids lung volumes using a jacket
plethysmograph

Fig 8:TV falls on induction and with bronchoscopy;
adequate tidal volumes achieved with IP 138-310 Kpa
o
o
o
TIVA or inhalation?
Which inhalation agent?
Recovery?

Steroids

Adrenaline?

Intubate after bronchoscopy?
Latex allergy
What is the manageemnet of a 3 year old child with known Latex allergy for a
correction of Talipes.
Risk groups?spina bifida, sensitivity to balloons and toys.
Screening: tests of low specificity. Elevation of IgE and clinical history most specific.
Management: Latex free environment. Prophylaxis?
Fluid therapy in children.
Describe the fluid management of a 4 week infant (4.5 kg) for laparotomy and
colostomy formation for Hirschprung disease.
.
Maintenance fluid:
Energy requirements determine fluid and calorie requirements: 3-10 kg: 100cal/kg/24 hr, older 75-35cal/kg/24 hr.
½ for metabolic needs and ½ for growth
Water: 100ml/kg for 1-10, 50 ml/kg for next 10 kg, and 20ml/kg for 10 kg above that. Holiday and Segar “The
maintenance need for water in parenteral fluid therapy pediatrics “19: 823-832
Glucose:
Dex Saline soln. Aim to provide 20-30% of calorie requirements. (25g/kg/24 hours is total calorie requirement)
Glucose requirements: 2-5mg/kg/min. 5 tends to cause hyperglycaemia and glycosuria and so dehydration.
Hypoglycaemia rare so do we need to give glucose containing solns. Neonate , Prem but keep to 2-5 mg/kg/min?
Electrolytes: Na 2.5mmol /100 cal. K 2 mmol/100 cal (0.185 saline can produce this.
Maintenance solutions: Dex/saline (4%/0.18%)
Maintenance fluid in the newborn and premie: Newborn decreased fluid requirement for first 2 days. Premies may
have increased fluid requirements due to insensible water loss from transepidermally and respiratory exchange. Na
requirements in premie babies increased to 2-3X. Potassium beware the myriad of causes of hyper and
hypokalaemia. Premies have low calcium so beware lowering after transfusion and albumin administration.
Replace with 10% calcium gluconate 20 mg/kg slowly
Administration of fluid in premies: avoid rapid changes in tonicity and BP to decrease risk of Intracerebral
haemorrage so give fluids by infusions.
Introperative fluid.
Balance salt soln for 3rd space and for initial blood loss until transfusion trigger. (3x blood loss). Note also the
expanding third space as increased trauma to bowel etc. Risks of using 0.9% saline and Hyperchloraemic acidosis.
When do you give colloid? Which colloid? Is albumin use still indicated? The premie is very oedematous.
Transfusion triggers. MABL=estimated blood volume x (starting hct-target hct)/ starting hct
Blood and componenets in 10mls/kg increments and then reassess.
Anatomical and Physiological differences between neonates and adults
CNS: Fontanelles. Myelination complete at 2. Spinal cord level. Fragile subependymal vessels.
Brain water high in neonates: implications for partition coeffeiciants of inhaltion agents. neonates have very low
solubility (50% lower brain-gas solubility for halothane) So washin is very quick. For Sevo with lower solubilities
no difference b/n infants and adults. Washin affected by FIAA, V, FRC, CO, solubility, Alv-venous pp. In
neonates increased washin since V increased. High CO goes to vessel rich group cf adults so this also increases
wash in. In R/L shunt prolonged induction ( effect more pronounced the less soluble the agent).
CBF decreased (30-40 ml/100g brain). Co2 reactivity attenuated. Asphyxiated neonate loses CBF/CPP
autoregulation.
MAC: peak at 1-6 mnths. Decrease. Also decreases with gestational age. Why?
Stress response present in neonates.
RS:
Control: C02 drive attenutated cf older infants. Increases with gestational and postnatal age. In premiie hypoxia
attenuates CO2 drive. (lasts 2-3mnths). Hypoxaemic drive complex; 1st mnth drive temperature dependent.
Respiratory reflexes present: Head. Hering-Breuer; inhibition of the inspiratory centre after inflation of lung.
The Ex premie and apnoea: Risk until 60wks PC? Cote et al 1995 Anesthesiology 82: 809-822: a metanalysis on
the factors that affect POA in expremies. 8 studies. Original data obtained. Single procedure (inguinal hernia). No
treatments. Standard defn of POA (>15s or accompanied by bradycardia). Those institutions that used continuous
recording had a predicted probability of apnoes to a greater PC age.
Risk of POA related to gestational age, PC age. Looked at 8 other risk factors but only risk factor was HCT. This
risk did not change with PC or GA in babies over 45 wks PC. If eliminate all anaemics and those with apnoea in
recovery only 77 babies left and only 1/77 had apnoea without apnoea pre or immediately postoperativly. 95%
confidence that risk is <1% if PC age 56 wks.
How can you reduce apnoeas: Avoid GA. Caffeine.
Upper a/w anatomy: Head, occiput, chin, nasal passages, tongue, Larynx posn, Epiglottis shape, Vocal cod
orintation, Shape of airway, cricoid narrowest point, epithelium at cricoid loose pseudostratified. Trachea short.
Lower airways:
RS mechanics in neonates: rib structure. intercostals muscles; less efficient fibre type, decreased elastin content.
Diaphragm: fibre content, orientation with abdominal wall, more susceptible to splinting.
Lung volumes. Vols in ml/kg
Variable
Neonate
adult
Note that BMR is increased as is apparatus dead space.
RR high, Alveolar ventilation is 100- 150 ml/kg/min, oxygen consumtion 2x.
PaO2 0-1wk: 70, 1-10:85, 4-8yrs:90,12-16yr: 96
CVS
Transition from foetal to neonatal circulation.
PPH
Myocardial function: Strength of contraction. HR dependent CO. Preload of limited value. Insensitivity to
Ionotropes
Uneven maturation of ANS
BR insensitive at birth
Regional anaesthesia very stable in neonates
HB changes
Type of Hb changes as well as no. of red cells
Renal:
Changes in total , ECF and ICF. Implications for Vd
GFR: Low(40% adult at one week). Newborn susceptible to fluid overload.
Tubular function: Concentrating ability poor. Unable to excrete large water load.Tubular resorption adult levels at
1 yr.
Hepatic: Glucose metabolism poor so risk of hypoglycaemia. Vit k dependent clotting factors low. Microsomal
liver function low. Oxidases mature by 6mnths. Phase 2 reactions glucorinadtion by 1 yr.
Neonate high K and low Ca. Low level of alpha 1 glycoprotein so ff of drugs like narcotics and LA are high..
Temperature: Limited in maintenaing thermal neutrality.
Cost of hypothermia is massive increase in oxygen consumption and acidaemia with consequent possible shunting
due to changes in PVR.
Neonatal Pharmacology
Uptake of volatiles fast: Va:FRC is 5;1 in neonates cf 1.5;1 in adults (BMR increases); Greater portion of blood to
vessel rich grp; high water content of blood and tissues reduce solubility of volatiles and reduce both blood/gas
and tissue/gas partition coefficients.
MAC: iso 1.6; sevo 3.3
Increased CVS sensitivity to volatiles> Preload before induction.
Avoid N2O: bowel gas; cardiovascular depressant. N 34 x less soluble so can increase oxygen levels much more
quickly when needed.
IV agents : Thio dose 60% child of 1-6 mnths; low porten binding, permeable BB, immature brain. CVS stability
even at 1.5x ED50 (3.4 mg/kg) but need atropine and fluid PL.
Diazepam very slow metabolism.
Morphine: increased sensitivity. Large II variability (10 fold range)(? Glucuronidation maturity). Limit infusion to
15ug/kg/hr. Fentanyl shows similar variability but dose lower.(decreased alph1 glycoprotein)